Inappropriate Heavy-Metal Ion Concentrations

Background information

From the water testing labs we have learned that our drinking water may contain many substances like calcium, iron, chloride and sulfates. These substances are typically not harmful to humans and some like calcium and iron are actually beneficial for us in small amounts. There are also substances that can be harmful to us, such as heavy metals. These metals are called "heavy" metals because their atoms have a greater mass than the essential metal elements (e.g iron, magnesium, etc). Two of the heavy metals that are of great concern in our water supply are two cations: Lead (Pb2+) and Mercury (Hg2+). These two cations are found in the environment because of their widespread use. Heavy metal ions are toxic to the environment because when consumed they can bind to proteins in your body, causing disruptions to the proteins performance. Enough exposure to heavy metal ions can cause damage to the nervous system, brain, kidneys and liver. They can be potentially lethal to you. Lead (Pb2+) is common in our environment because of its use in many familiar substances like pottery, automobile batteries and paint. Lead paint was outlawed in 1978. Lead was also used as a chemical in automobile gasoline resulting in lead oxide emissions. Although the use of lead has begun to phase out it still may remain in the soil surrounding heavily trafficked roads or in the soil of homes built before 1987. Mercury can be found in our environment due to its use as an electrical conductor. It can be found in very small amounts in CFC light bulbs. Typically they are not harmful, if disposed of properly. It also can be found in some scientific instruments and weather thermometers.Since it is toxic, it might also be used in eliminating bacteria, fungi, and pests when used in antiseptics, fungicides, and pesticides.

Pre-Lab

1.) Why are heavy metals referred to as heavy?
2.) What are two examples of heavy metals?
3.) Why are heavy metals harmful to you?
4.) What is a cation?
5.) Predict why you might find heavy metals in our environment.

Procedure

Read the description of each neighborhood and decide if they may be at risk for heavy metal contamination and why?

Sunnyvale
A happy community of homes that were constructed in the early 1970s. The community is a safe one and far away from any sort of manufacturing or chemical plants. Most of the homes are in good condition and very few have ever needed to be repainted.

Warton
Warton is a new industrial city that earns a lot of its revenue from manufacturing. Most of what they manufactur is weather instruments for commerical distribution. All of the homes were built within the past 10 years. There are four major roads entering the city and they are highly traveled. Other than the noise, Warton seems like a great place to live.

Greendale
Greendale is an environmentally friendly city, located by the ocean. Most people don't own cars here, they just walk to where they need to go. Big on saving energy, CFC bulbs are a requirement in every home. Since they go through so many bulbs, they haven't quite found a proper way to dispose of them.

Farmtown
A small rural community which has very few roads that are traveled. Most of the homes are small farm homes that having been repainted since the 1960s. Recently, they have had problems with pests in their crops and have begun to use agricultural pesticides to spray them.

Data

List the risks for lead and mercury for each city.

Analysis

1.) What could Sunnyvale due to minimize their risk for heavy metal poisoning?
2.) What could Warton due to minimize their risk for heavy metal poisoning?
3.) What could Greendale due to minimize their risk for heavy metal poisoning?
4.) What could Farmtown due to minimize their risk for heavy metal poisoning?
5.) What risks could Killingly have for heavy metal poisoning?

Conclusion

List three things that you learned from this activity.